According to Scottish lore, Ghillie Dhu was a nature spirit clothed in leaves and moss. The being was said to be mostly shy and reclusive but was also reported to have a wild side. Ghillie Dhu seemingly had a soft spot for children. He sheltered a noble child who was lost in the forest and returned her to her home - saving her life. While sightings of the creature continued to occur in the area, Ghillie Duh only revealed himself to her. This led to suspicion by her father and hunters were brought in to capture him. Ghillie Dhu was never found and the child never saw the Ghillie Dhu again.
Ghosts are disembodied spirits tied to the physical world by some task left unfulfilled during their lives on earth. Often they appear as transparent likenesses of their former selves.
Giants are simply larger versions of humans and while not always malevolent, this trait makes them appear intimidating. Jack and the Beanstalk and David and Goliath may be the two most well known tales with references to giants. Early religious texts describe a race called the Nephilim which were created when Angels came down from the heavens and mated with mortal women, creating a race of monstrous beings who were then wiped out by a great flood.